Apparatus for deploying an air bag through a hard panel

ABSTRACT

An apparatus for deploying an air bag through an automotive dash panel ( 12 ) includes an air bag door ( 16 ) integrally formed in the panel and defined by a door perimeter including a frangible edge ( 18 ) of reduced cross section. A dispenser ( 20 ) supports the air bag ( 24 ) behind the door. A metal reaction plate ( 28 ) is positioned between the air bag ( 24 ) and the door ( 16 ). When the air bag inflates, it forces the reaction plate ( 28 ) to bend around a horizontal hinge line ( 36 ). As the reaction, plate pivots it concentrates inflation force along a lower portion of the frangible door edge. This helps to predictably separate the door from the dash panel by tearing along the lower door edge and allowing the tear to propagate up two side edges. In one embodiment, the tear also propagates across an upper edge to completely separate the door from the panel. At least one, and preferably two or three tethers ( 50 ) limit how far the door can travel during air bag inflation. A stop member may be included to limit reaction plate bending. After deployment, the reaction plate remains in a position that prevents the door from returning to its original position. A retaining structure may be included to preclude at least a portion of the air bag door from tearing free of the vehicle panel. A hinge ( 44 ) may be embedded in the panel in a position spanning a portion of the door perimeter. A hollow channel may be formed into the panel along the frangible marginal edge to create a substantial strength differential with the door perimeter to promote bending along the hinge and/or to help confine tearing to the frangible marginal edge during air bag deployment.

This application is the National Stage of International Application No.PCT/US99/13592, filed Jun. 16, 1999, which is a Continuation in Part ofU.S. patent application Ser. No. 08/949,842, filed Oct. 14, 1997, U.S.Pat. No. 5,941,558, which is a Continuation in Part of U.S. patentapplication Ser. No. 08/871,243, filed Jun. 9, 1997, now abandoned. Thisapplication also claims priority of U.S. provisional application Ser.No. 60/089,836 filed Jun. 19, 1998 and Ser. No. 60/089,863 filed Jun.19, 1998.

TECHNICAL FIELD

This invention relates generally to a passive supplemental inflatablerestraint (PSIR) system having an air bag door that is integrally formedwith an instrument panel and, more particularly, to such a system havingan air bag door integrally formed with a hard first-surface instrumentpanel and configured to break and/or tear open in a predictable way.

BACKGROUND OF THE INVENTION

An inflatable restraint system having an air bag door that is integrallyformed into an automotive vehicle instrument panel must include someprovision for guiding or otherwise facilitating the opening and partialseparation of that air bag door from the instrument panel that the dooris integrally formed with. The air bag door in such a system opens toprovide a path for an air bag to deploy through. It is desirable thatwhatever such provision is made includes some means for insuring thatthe air bag door breaks and/or tears open in a generally predictableway. This is true for driver-side inflatable restraint stems (DSIRs),passenger-side inflatable restraint systems (PSIRs) and inflatablerestraint systems in vehicle door panels, quarter panels or othersidewall structures. It is also desirable for such systems to includemeans for insuring that portions of the door do not separate from thesystem when the air bag deploys and forces the door open.

The need to control breakage and/or tearing is particularly importantwith air bag doors that are integrally formed into hard first-surfaceinstrument panels. The “first-surface” of a panel is the cosmeticexterior surface that would be visible to a vehicle occupant. Hardfirst-surface panels are typically formed by injection molding one ormore plastic materials.

To close air bag deployment openings in hard first-surface instrumentpanels, many current PSIR systems use a separate “add-on” air bag door.One reason that current PSIR systems add on a separate air bag door insuch applications is because it is difficult to cause a tear seam in anintegrally formed door to break and/or tear in a predictable way underthe sudden shock of a deploying air bag. Even when weakened, a tear seamthat integrally joins an air bag door and a surrounding instrument panelcan fracture in a ragged unpredictable manner that can affect air bagdeployment.

One example of a hard first-surface system is disclosed in U.S. Pat. No.5,472,228 assigned to Morton International and issued Dec. 5, 1995. Thispatent discloses a reinforced hard door with a reaction plate. When theair bag deploys, the reaction plate forces the door in a direction thatwill break weakened fasteners securing the door to an instrument panel.

Another of Morton's hard door concepts is shown in U.S. Pat. No.5,533,746, issued Jul. 9, 1996. This system includes a reaction platewith reinforced lands. When the air bag deploys, it acts upon thereaction plate to cause hold down attachment rods to release from clips.

To control tearing and/or breaking, air bag doors that are integrallyformed with automotive trim or instrument panels will sometimes includefrangible marginal edges which are regions of weakened materials,reduced thickness or scoring and are commonly referred to as “tearseams.” Tear seams are weak areas designed to tear and/or break when anair bag inflates and forces the door to open. Some of these systems alsoemploy tethers and/or hinges that retain the air bag door to theinstrument or trim panel after the door has torn and/or broken open. Forexample, U.S. Pat. No. 5,569,959, issued to Cooper et al., discloses aninflatable restraint assembly comprising an air bag door retainerportion integrally formed in an automotive instrument panel retainer anddefined by a door perimeter. A frangible marginal edge or tear guide isincluded in a skin cover disposed over a foam layer that extends acrossthe door opening. A metal hinge panel is embedded within the instrumentpanel retainer and spans a portion of the door perimeter. Cooper et al.also disclose a method for making such an inflatable restraint assembly.The method includes pre-molding the hinge panel into the hard instrumentpanel retainer portion such that the hinge panel spans the doorperimeter.

With many current systems, the tear seams and/or hinges are formed in ahard instrument panel retainer portion rather than a skin cover. Thiscan be done by a secondary operation such as casting weakened material,or cutting, grinding or laser scoring performed after a manufacturingstep of integrally molding the instrument panel and door. Currentsystems also include tear seams formed in back surfaces opposite theouter class-A surfaces of integral instrument panel/air bag doorstructures to improve the aesthetic appearance of the instrument panelby concealing the presence of the door.

At least one automotive instrument panel, as shown and described in U.S.Pat. No. 5,162,092, issued to Klobucar et al., discloses an instrumentpanel having a tubular channel and a method for forming the channel inthe panel. The tubular channel is integrally formed in the panel byinjecting gas into molten panel material in a mold. The tubular channelin the Klobucar et al. instrument panel adds structural rigidity.However, Klobucar et al. does not disclose an air bag door or any othersupplemental inflatable restraint component.

What is needed is an apparatus that, in response to air bag deployment,more cleanly and predictably separates and opens an air bag door that isintegrally formed into an instrument panel. What is also needed is suchan apparatus that helps separate and open an air bag door that isintegrally formed into a hard first-surface instrument panel.

SUMMARY OF THE INVENTION

According to the invention, an inflatable restraint assembly for anautomotive vehicle is provided that comprises a reaction plate thatincludes an integral tether. The tether is connected to a supportstructure and is integrally connected to a pivotable panel portion ofthe reaction plate. The support structure comprises an interior vehiclepanel. An air bag deployment door is integrally formed in the vehiclepanel. At least a portion of a perimeter of the door is defined by afrangible marginal edge. An air bag dispenser is supported adjacent adoor inner surface. An air bag is supported in an air bag receptacle ofthe air bag dispenser. The air bag has an inner end operativelyconnected to the air bag dispenser and an outer end disposed adjacentthe air bag deployment door. The air bag dispenser is configured todirect air bag deployment through an air bag receptacle opening andalong a deployment path through the vehicle panel. The reaction plate isdisposed between the air bag and the air bag deployment door and isconfigured to receive the force of air bag deployment from the dispenserand to direct and distribute that force against the door inner surfaceto separate the door from the vehicle panel along the frangible marginaledge of the door. The pivotable panel portion of the reaction plate isconfigured to pivot outward under the force of air bag inflation whilebeing securely retained by the integral tether. The reaction plate andintegral tether cooperate to provide an opening motion that cleanlyseparates the air bag door along the frangible marginal edge.

According to another aspect of the invention, the reaction platecomprises a plastics material such as thermoplastic urethane.

According to another aspect of the invention, a plurality of integralribs extend integrally inward from an inner surface of the pivotablepanel portion of the reaction plate to provide additional structuralstiffness to that portion of the plastic reaction plate.

According to another aspect of the invention, the integral tether isconnected to the support structure by a sliding hinge. The sliding hingeallows the reaction plate to slide outwardly when the air bag deploysand forces the reaction plate to pivot outward. This outward motionprevents the pivotable panel portion of the reaction plate from bindingagainst an upper edge of the opening left by the opening of the air bagdeployment door during air bag deployment.

According to another aspect of the invention, the integral tether isconnected to the support structure by a fastener and the sliding hingeincludes a slotted fastener hole in the integral tether configured toslidably receive a shaft portion of the fastener to allow the integraltether to slide outwardly.

According to another aspect of the invention, the integral tetherincludes fanfolds configured to allow the tether to elongate when adeploying air bag forces the reaction plate outward. As with the slidinghinge, the fanfolds provide outward motion that prevents the pivotablepanel portion from binding against the upper edge of the air bagdeployment door opening during air bag deployment.

According to another aspect of the invention, a tubular channel isdisposed along at least a portion of the air bag door perimeter. Thetubular channel is disposed opposite an outer surface of the air bagdoor and vehicle panel. A second structural channel may be disposedadjacent and parallel to the first tubular channel with the perimeterdisposed between the first and second tubular channels. One of thetubular channels is integrally formed with the door and the othertubular channel is integrally formed with the vehicle panel. The tubularchannels confine tearing to the perimeter without adding a significantamount of material that can cause sinks in the outer surface.

According to another aspect of the invention, a screw boss integrallyextends inward from one of the tubular channels and is configured toreceive a fastener connecting the reaction plate tether portion to thescrew boss. The tubular channel reduces the chance that sinks mightdevelop in the outer surface of the panel beneath the screw boss. Atubular channel may also extend integrally inward from the inner surfaceof the door with a screw boss integrally extending inward from thattubular channel. In this case, the screw boss is configured to receive afastener connecting the reaction plate to the screw boss.

According to another aspect of the invention, the air bag deploymentdoor includes a marginal edge that forms a hinge between the vehiclepanel and the door. The hinge includes a hinge panel comprising a secondmaterial embedded at least partially within the first material andspanning the door perimeter. The second material includes any one ormore materials from a group of materials including thermoplastic rubber,glass matte, fabric and metal.

According to another aspect of the invention, the perimeter of the airbag door is generally shaped to approximate the shape of the air bagcanister opening.

According to another aspect of the invention, a method for making aninflatable restraint assembly is provided. The method includes providinga mold configured to form the shape of the integral air bag door andtrim panel and the tubular channel. Material is then provided in themold and gas is injected into a portion of the material disposed in aportion of the mold configured to form the tubular channel. The materialis then allowed to solidify within the mold and the solidified materialis removed from the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

To better understand and appreciate the invention, refer to thefollowing detailed description in connection with the accompanyingdrawings:

FIG. 1 is a perspective view of a first passive restraint systemconstructed according to the present invention and installed in avehicle dash panel;

FIG. 2 is a cross-sectional end view of the passive restraint system ofFIG. 1;

FIG. 3 is an exploded view of the passive restraint system of FIG. 1;

FIG. 4 is a cross-sectional end view of a second passive restraintsystem constructed according to the present invention;

FIG. 5 is a fragmentary perspective view of an air bag door of thepassive restraint system of FIG. 4;

FIG. 6 is a fragmentary perspective view of the air bag door of FIG. 5installed in a vehicle dash panel;

FIG. 7 is a cross-sectional end view of the passive restraint system ofFIG. 4 during air bag inflation;

FIG. 8 is a cross sectional view of a heat-stake pin of the passiverestraint system of FIGS. 1 and 2;

FIG. 9 is a perspective view of a third passive restraint systemconstructed according to the present invention and installed in avehicle dash panel;

FIG. 10 is a cross-sectional view of the passive restraint system ofFIG. 9 taken along line 10—10 of FIG. 9;

FIG. 11 is a cross-sectional view of the passive restraint system ofFIG. 9 taken along line 10—10 of FIG. 9 during air bag inflation;

FIG. 12 is a first cross-sectional view of a fourth passive restraintsystem constructed according to the present invention;

FIG. 13 is a cross-sectional view of the passive restraint system ofFIG. 12 during air bag inflation;

FIG. 14 is a cross-sectional view of the passive restraint system ofFIG. 12 taken through a screw boss of the system;

FIG. 15 is a cross-sectional view of the passive restraint system ofFIG. 12 taken through a screw boss of the system during air baginflation;

FIG. 16 is a cross-sectional view of the passive restraint system ofFIG. 12 taken along line 16—16 of FIG. 14;

FIG. 17 is a partial cross-sectional view of the passive restraintsystem of FIGS. 9–11 including an alternative tether attachmentconstruction;

FIG. 18 is a cross-sectional view of an air bag door hinge constructedaccording to the present invention;

FIG. 19 is a cross-sectional view of a break-away/tear seam of a firstembodiment of an integral air bag door and instrument panel constructedaccording to the invention;

FIG. 20 is a cross-sectional view of a break-away/tear seam of a secondembodiment of an integral air bag door and instrument panel constructedaccording to the invention;

FIG. 21 is a cross-sectional view of a break-away/tear seam of a thirdembodiment of an integral air bag door and instrument panel constructedaccording to the invention;

FIG. 22 is a partial perspective bottom view of the integral air bagdoor and instrument panel of FIG. 19;

FIG. 23 is a partial perspective bottom view of the integral air bagdoor and instrument panel of FIG. 20; and

FIG. 24 is a partial perspective top view of the integral air bag doorand instrument panel of FIG. 21;

FIG. 25 is a front perspective view of an instrument panel including anair bag door integrally formed in an instrument panel retainer accordingto the invention and defined by a 360° tear seam;

FIG. 26 is a side cross-sectional view of an air bag canister assemblyconstructed according to the invention and installed behind theinstrument panel of FIG. 25;

FIG. 27 is a perspective view of the air bag canister assembly of FIG.26;

FIG. 28 is a magnified view of the regions in FIG. 26 bounded by CircleA;

FIG. 29 is an enlarged partial cross-sectional view of an alternativeboss construction;

FIG. 30 is a side cross-sectional view of an air bag canister assemblyconstructed according to the invention and installed behind aninstrument panel having an integral air bag door defined by a 270° tearseam;

FIG. 31 is a side cross-sectional view of an air bag canister assemblyhaving a plastic reaction plate constructed according to the inventionand supported by an integral slotted tether strap;

FIG. 32 is a front perspective view of the reaction plate of FIG. 31;

FIG. 33 is a side cross-sectional view of an air bag canister assemblyhaving a plastic reaction plate constructed according to the inventionand supported by an integral fanfold tether strap;

FIG. 34 is a front perspective view of the reaction plate of FIG. 33;and

FIG. 35 is a die view of the tear seam pattern of the integral air bagdoor of FIG. 25.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A first embodiment of an inflatable restraint assembly for an automotivevehicle is generally indicated at 10 in FIGS. 1–3. A second embodimentis generally indicated at 10′ in FIGS. 4–7. A third embodiment isgenerally indicated at 10″ in FIGS. 9–11. Reference numerals with thedesignation prime (′) in FIGS. 4–7 and double prime (″) in FIGS. 9–11indicate alternative configurations of elements that also appear in thefirst embodiment. Where a portion of the following description uses areference numeral to refer to the figures, we intend that portion of thedescription to apply equally to elements designated by primed numeralsin FIGS. 4–7 and double-primed numerals in FIGS. 9–11.

An alternative construction of the third embodiment is generallyindicated at 10 b in FIG. 17. Reference numerals with the suffix “b” inFIG. 17 indicate elements of FIG. 17 that correspond to similar oridentical elements shown in FIGS. 9–11. Where a portion of thedescription of the third embodiment uses a reference numeral to refer tothe figures, we intend that portion of the description to apply equallyto elements designated by the suffix “b” in FIG. 17.

In FIG. 1, the inflatable restraint assembly is shown hidden behind anautomotive vehicle passenger-side dash panel 12 below a windshield 14 ofthe vehicle. As shown in FIG. 2, the apparatus includes the panel 12,and an air bag deployment door 16 integrally formed in the panel 12 andhaving a perimeter defined, in part, by a hidden marginal edge 18. Theperimeter may, also be defined as the lateral boundary of the door16—the door 16 being defined as that portion of the integrally formedpanel 12 and 5 door 16 that is separable or bendable from the panel 12under the force of air bag inflation. The door 16 and the vehicle dashpanel 12 are integrally formed as a single unitary piece.

As shown in FIGS. 2 and 3, an air bag dispenser assembly 20 is supportedbehind the door 16, i.e., on a side of the door 16 opposite a door outersurface 22. The dispenser 20 is also disposed adjacent and aligned withthe air bag deployment door 16. As is best shown in FIG. 2, the air bagdispenser 20 is configured to direct air bag deployment along adeployment path through the door 16 of the vehicle panel 12, the air bagdeployment path being the path that the air bag will travel along as itinflates during deployment. The air bag deployment path is bestexemplified by the respective areas occupied by the inflated air bagsshown at 24′ in FIG. 7, 24″ in FIG. 11, and at 24 s in FIGS. 13 and 15.The dispenser 20 may be any suitable type of air bag dispenser toinclude, for example, the dispenser described in U.S. Pat. No. 5,564,731and incorporated herein by reference.

An air bag 24 is supported in an air bag receptacle 26 of the air bagdispenser 20 and is operatively connected to the air bag dispenser 20 atan open end 27 of the air bag 24. A closed outer end 30 of the air bag24 is disposed adjacent the air bag 24 deployment door 16.

As is best shown in FIG. 2, a rigid metal reaction plate 28 is disposedbetween the air bag 24 and the air bag deployment door 16. The reactionplate 28 receives the force of air bag deployment when the air bag 24inflates and expands out of the dispenser 20. The reaction plate 28directs and distributes that force across the door 16 to predictablyseparate the door 16 from the panel 12 along the hidden margin edge 18of the door 16. By distributing the air bag 24 opening force across thedoor 16 the reaction plate 28 also serves to prevent air bag 24 openingforces from concentrating in other locations on the door 16 that mightresult in door 16 or panel 12 fractures and/or fragmentation. In thepresent embodiment, the reaction plate 28 is positioned to concentrateair bag opening forces along a portion of the hidden marginal edge 18that extends along the forward marginal edge 46 of the door 16. Thereaction plate 28 is positioned in this way to initiate marginal edgetearing at the forward marginal edge 46 and then allow the tearing topropagate upward along the two side edges of the door 16. Alternatively,marginal edge tearing may be initiated at the forward marginal edge 46and along the two side edges virtually simultaneously. The reactionplate 18 is preferably made of cold rolled steel but may be made fromany other material having suitable bending and force-distributingcharacteristics.

As is best shown in FIG. 3, the reaction plate 28 includes a reactionplate outer marginal edge 32 having a shape generally identical to thatof the hidden marginal edge 18 of the air bag deployment door 16. Thereaction plate marginal edge 32 is aligned with the hidden marginal edge18 of the air bag deployment door 16 to concentrate air bag 24 inflationstress along the hidden marginal edge 18 of the air bag deployment door16.

As shown in FIG. 2, the reaction plate 28 is pivotally attached along areaction plate inner edge 34 to the air bag dispenser apparatus 20.However, in other embodiments, the reaction plate 28 may be pivotallyattached to a portion of the panel 12 or other surrounding supportstructures. An outer pivotable portion of the reaction plate 28,generally indicated at 35 in FIGS. 2 and 3, is outwardly and upwardlypivotable away from the air bag dispenser 20. The outer reaction plateportion 35 pivots by bending along a first horizontal hinge line 36 ofthe reaction plate 28 that extends parallel to and adjacent the rigidlyattached inner plate edge 34. The hinge line 36 defines a marginal inneredge of the outer portion 35 of the reaction plate. A pivotable lowerpanel portion 42 of the reaction plate also pivots by bending along asecond horizontal hinge line 37 of the reaction plate 28 that extendsparallel to the first hinge line 36. The force of an inflating air bagcauses the outer portion 35 of the reaction plate 28, which includes thepivotable lower panel portion 42 of the reaction plate 28, to pivotoutward. The pivotable lower panel portion 42 of the reaction plate 28then continues pivoting, due to angular momentum acquired from air bagdeployment, into a position angularly spaced from the air bag deploymentpath and more than 45 degrees from its position before air bagdeployment. Examples of such an angularly spaced position of the lowerpanel portions of reaction plates are shown by reference to lower panelportions 42′ and 42″ in FIGS. 7 and 11, respectively.

As shown in FIG. 2, the outer portion 35 of the reaction plate 28 isdisposed adjacent a door inner surface 38 and opposite the outer doorsurface 22. As is best shown in FIG. 2, the outer portion 35 and,therefore, the pivotable lower panel portion 42 of the reaction plate 28are separate from the door 16. This allows the outer portion 35 andpivotable lower panel portion 42 of the reaction plate 28 to moveindependently of the door 16 following door separation. This preventsthe outer portion 35 of the reaction plate 28 from arresting orrestricting the opening motion of the door 16.

Three horizontal ribs, shown at 40 in FIGS. 2 and 3, extend integrallyinward from the door inner surface 38 to a point adjacent the pivotablelower panel portion 42 of the outer portion 35 of the reaction plate asshown in FIGS. 2 and 3. The ribs 40 space the reaction plate lower panel42 from the door inner surface 38. The ribs 40 allow the reaction plate28 to be positioned in a plane that is generally perpendicular to thedirection of air bag 24 deployment while remaining in close proximity tothe door 16. The ribs 40 also allow the door 16 to be designed withouter contours that do not necessarily correspond to the reaction plate28 configuration. In other embodiments, the ribs 40 may be of anysuitable configuration and orientation known in the art.

As shown in FIGS. 1–3, the air bag deployment door 16 has a curvedrectangular shape defined by relatively straight aft 44 and forward 46marginal edges and a pair of arcade side marginal edges 48. The forward46 and side 48 edges comprise a frangible region of reduced crosssection. The rear edge 44 may comprise a sling seam or groove intendedto define the rear edge 44 of the door 16. In other embodiments, therear edge 44 may be hidden or there may be no “rear edge”. In otherwords, the transition from the door to the panel 12 may beuninterrupted.

Where a styling seam is used, it may be functional or merely aesthetic.Where the styling seam is functional, it may be adapted to act as abending hinge 44 when the door 16 is forced open and separated from thesurrounding vehicle panel 12 along the frangible forward 46 and side 48marginal edges. The bending hinge 44 allows the door 16 to swing outwardand upward from the panel 12 during air bag 24 deployment whileretaining the door 16 to the panel 12. Alternatively, the styling seammay also be designed as a frangible region of reduced cross section insimilar fashion to the forward 46 and side 48 edges.

A first pair of flexible tethers is generally indicated at 50 in FIGS. 2and 3. Each tether comprises PVC-coated nylon, has an outer end portion52 fastened to the door inner surface 38, and an inner end portion 54fastened to the air bag dispenser assembly 20. In other embodiments, thefirst pair of flexible tethers 50 may be fastened to the panel 12 orother adjacent support structures instead of the dispenser 20. Thetethers 50 may incorporate any one or more of a number of differenttether constructions known in the art. One example of an acceptabletether construction is disclosed in U.S. Pat. No. 5,564,731, is assignedto the assignee of the present invention and is incorporated herein byreference.

The inner end portion 54 of each tether 50 of the first pair of tethersis fastened to the air bag dispenser assembly 20 at a tether controlpoint shown at 56 in FIG. 2 adjacent the reaction plate inner edge 34.The tether inner end portions 54 are fastened by folding them within aU-shaped channel 58 formed along the reaction plate inner edge 34. Asshown in FIG. 3, a row of holes 60 is formed along each side of theU-shaped reaction plate channel 58 to receive fasteners 62 that attachthe reaction plate 28 to an elongated rectangular air bag dispenserflange 64. The dispenser flange 64 is horizontally disposed and extendsintegrally upward from the air bag dispenser apparatus 20. The flange 64includes a row of flange holes 66 corresponding to the holes in theU-shaped reaction plate channel 58. One or more of the fasteners thatconnect the reaction plate 28 to the dispenser assembly 20 also passthrough the portion of each tether inner end 54 that is folded withinthe U-shaped channel 58.

As is best shown in FIG. 2, the outer end portion 52 of each tether 50of the first pair of tethers is fastened to the door 16 by eightheat-staked pins 68. The pins 68 extend integrally inward from the airbag 24 deployment door 16 as shown in FIG. 8. The pins 68 are preferablyformed with the door 16 and the vehicle panel 12 as a single unitarypiece. Other embodiments may use hot staked bosses as disclosed in U.S.Pat. No. 5,564,731, assigned to the assignee of the present inventionand incorporated herein by reference. Still other embodiments may usescrews 76 b engaged with screw bosses as is representatively shown at 67in FIG. 17. The screw bosses 67 may be integrally formed to extendinward from the door 16. The bosses 67 may be threaded or unthreaded foruse with self-tapping screws. Other embodiments may use any number ofsuitable fastening means known in the art.

The bag inflatable restraint assembly 10 described above is optimized toopen integral doors in vehicle trim panels, comprising hard outer or“first” surfaces, e.g., injection-molded panels. However, the inventionmay also be used where, as shown in FIG. 2, the hard outer surface iscovered with a flexible skin 69 or skin 69 and foam 71 layers. In otherwords, a flexible skin 69 may be applied to cover at least a portion ofthe vehicle dash panel 12 and/or air bag deployment door 16 in a layereddisposition. A foam layer 71 may also be included between the skin 69and a portion of the panel 12 and/or the door 16.

The door 16 and panel 12 preferably comprise an injection moldedpolycarbonate/acrylonitrile butadiene styrene blend (PC/ABS) orpolypropylene. Examples of acceptable PC ABS formulations include GE MC8002 and Dow Pulse # 830. An example of an acceptable polypropylene isMontell #BR33GC. Other suitable materials may include polyesters,polyurethanes, polyphenylene oxide, polystyrenes, polyolefins, orpolyolefin elastomers.

According to the second embodiment of the invention shown in FIGS. 4–7,the air bag deployment door 16′ is defined by a visible marginal edge18′ and includes eight doghouse-shaped fastener brackets 70. Eachfastener bracket 70 extends integrally inward toward the air bagdispenser assembly 20′ from the door inner surface 38′ in place of theribs 40 of the first embodiment. Each fastener bracket 70 includes anattachment surface 72 spaced inwardly from and supported generallyparallel to the door inner surface 38′. The fastener brackets 70 arepreferably integrally formed with the door 16′ and the vehicle dashpanel 12′ as a single unitary piece.

The first tether 50′ of the second embodiment makes up a portion of asingle continuous tether sheet rather than comprising two separatetethers as in the first embodiment. As shown in FIGS. 4–7, an outer end52′ of the first tether 50′ is attached to a forward portion 74 of thedoor 16′ adjacent a forward marginal edge 46′ of the door 16′ disposedopposite the hinge 44′. More specifically, four rivets 76 attach theouter end 52′ of the first tether 50′ to the attachment surfaces 72 offour fastener brackets 70 formed on the forward portion 74 of the door16. The fastener brackets 70 support the rivets 76 without affecting theaesthetic continuity of the outer door surface 22′. In otherembodiments, other fastener bracket configurations including heatstaking pins and screw bosses and other suitable types of fasteners andfastening methods may be used as is known in the art.

As shown in FIGS. 4 and 7, each fastener bracket 70 includes a fasteneraperture 78 disposed through the attachment surface 72 of the bracket 70to receive one of the rivets 76. Each rivet 76 comprises a shaft portionthat extends through the aperture 78 and through a hole formed in thefirst tether 50′ to hold the first tether 50′ to the fastener bracket 70in conventional fashion.

The four fastener brackets 70 that attach the first tether 50′ to thedoor 16′ extend integrally inward from the door inner surface 38′adjacent a lower marginal region of the door 16′ to a point adjacent thereaction plate 28′. Similar to the ribs 40 of the first embodiment, thefastener brackets 70 present the reaction plate lower panel 42′ in aplane more perpendicular to the direction of air bag 24′ deployment fromthe dispenser 20′. In other words, the fastener brackets 70 span thespace between the outwardly curved lower marginal door region and thegenerally vertical reaction plate lower panel 42′.

The single continuous tether sheet that includes the first flexibletether 50′ also includes a second flexible tether, generally indicatedat 80 in FIGS. 4 and 7. The second tether 80 has an inner end portion 82fastened to the air bag dispenser assembly 20′ at the tether controlpoint 56′. In other embodiments, the second tether 80 may be securedeither to the panel 12′ or to another adjacent structure. The secondflexible tether 80 has an outer end portion, shown at 84 in FIGS. 4 and7, that is fastened to an aft portion 86 of the door 16′ disposedbetween the forward door portion 74 and the hinge 44′. The second tether80 ties the aft door portion 86 to the control point 56′ to prevent anyportion of the door from over-pivoting towards the windshield 14 andbreaking off at one of several potential bending points including thehinge 44′.

As shown in FIGS. 4 and 7, the respective inner ends 54′, 82 of thefirst 50′ and second 80 tethers are riveted to an elongated rectangularflange 64′ 5 at the tether control point 56′. The flange 64′ extendsintegrally upward from the air bag receptacle portion 26′ of the air bagdispenser assembly 20′. The tether inner ends 54′, 82 are sandwichedbetween the flange 64′ and an elongated metal bar 90. Rivets 92 passthrough the flange 64′, the tethers 50′, 80 and the bar 90.

The air bag receptacle 26′ includes a mouth 94 disposed adjacent the airbag deployment door 16′. The mouth 94 has a width measured across themouth in a direction perpendicular to the hinge 44′, i.e., in agenerally vertical direction. The hinge 44′ is spaced from the mouth 94a distance equal to at least half of the mouth width. The hinge 44′ isdisplaced in this manner to reduce the maximum opening angle at thehinge 44′ to reduce material deformation and stress in the hinge duringair bag 24 deployment.

A pair of rigid stop members, representatively indicated at 96 in FIG.7, are operatively connected to the reaction plate 28′ and the air bagdispenser 20′. The stop members 96 limit reaction plate 28′ openingtravel. The stop members 96 may arrest the reaction plate 28′ in aposition that will prevent the door 16′ from returning to its originalposition after air bag 24′ deployment. Each stop member is preferablyfabricated from steel but may be made of other suitably rigid materials.

The stop members 96 are slidably supported in slots representativelyshown at 98 in FIG. 7 and disposed at opposite lateral sides of thereceptacle portion 26′ of the air bag dispenser apparatus 20′. Each stopmember 96 is fixed to the reaction plate 28′ at a stop pointrepresentatively shown at 100 in FIG. 7. The stop point 100 is disposedbetween the first hinge line 36′ and a reaction plate outer marginaledge 32′ disposed opposite the reaction plate inner edge 34′.

The outer panel portion 42′ of the reaction plate 28′ is outwardly andupwardly pivotable away from the air bag dispenser 20′ by bending thereaction plate 28′ along a second horizontal hinge line shown at 102 inFIG. 7. The second hinge line 102 is disposed horizontally across thereaction plate 28′ adjacent the stop point 100 and extends generallyparallel to the first hinge line 36′. The second hinge line 102 isspaced approximately one-third the distance between the first hinge line36′ and the reaction plate outer marginal edge 32′. This double hingearrangement allows the reaction plate 28′ to bend into an outwardlypivoted and upwardly extended position. In this position the plate 28′prevents the air bag deployment door 16′ from rebounding off the tethers50′, 80 and returning to its original position immediately after adeploying air bag 24′ has forced the door 16′ open.

Each stop member 96 is an elongated steel pin having a cylindrical shaftportion 104 as is representatively shown in FIG. 7. Inner 106 and outer108 circular disk-shaped stop flanges are disposed at respective innerand outer distal ends of the shaft portion 104 of each stop member 96.The inner stop flange 106 of each stop member 96 extends radially andintegrally outward from the shaft portion 104. The outer stop flange 108of each stop member 96 is preferably fixed to the reaction plate 28′ byspot welding or arc welding.

The elongated slots 98 on either side of the air bag receptacle 26′ eachhave a width slightly greater than that of the shaft portion 104 of eachstop member 96. The shaft portion 104 of each stop member 96 is slidablydisposed within one of the slots 98 to allow the stop members 96 to movebetween pre-inflation stowed positions, representatively shown in FIG.4, and post-inflation deployed positions, representatively shown in FIG.7. The reaction plate 28′ pulls the stop members 96 from the stowedposition to the deployed position when the reaction plate 28′ opensunder the force of an inflating air bag 24′. When the stop members 96reach their deployed positions the inner stop flanges 106 engage theslot 98 and arrest reaction plate 28′ movement. The stop members 96arrest the reaction plate 28′ in a position to prevent the door 16′ fromreturning to its original position following air bag deployment.

According to the third embodiment of the invention shown in FIGS. 9–11,the frangible marginal edge 18″ defines the entire perimeter of the airbag deployment door 16″. In other words, the frangible marginal edge 18″extends completely around the air bag deployment door 16″ in an unbrokencircuit as is best shown in FIG. 9. A pair of flexible tethers,representatively indicated at 50″ in FIGS. 10 and 11, is fastenedbetween the air bag deployment door 16″ and the reaction plate 28″. Eachtether 50″ includes an inner end portion 82″ fastened to the door 16″,an outer end portion 84″ fastened to the door 16″ and a middle portion83 fastened to the reaction plate 28″ between the second hinge line 102″and the reaction plate outer marginal edge 32″. The middle portion 83 ofeach tether 50″ is disposed approximately midway between the inner 82″and outer 84″ end portions of each tether 50″.

The air bag deployment door 16″ includes only four of the fastenerbrackets 70″ disposed in a rectangular pattern as shown in FIG. 9. Theinner end portion 82″ and outer end portion 84″ of each tether 50″ arefastened to the attachment surface of one of the four fastener brackets70″ by rivets 76″ as shown in FIGS. 10 and 11. As is also shown in FIGS.10 and 11, the middle portion 83 of each tether 50″ is fastened to thereaction plate 28″ between the second hinge line 102″ and the reactionplate outer marginal edge 32″ by a rivet 110.

As shown in FIGS. 9–11, nine vertical door ribs 112 extend integrallyinward from the door inner surface 38″ to a point adjacent the reactionplate 28″. 24 short horizontal door ribs 114 connect adjacent verticaldoor ribs 112 to form a rectangular grid pattern best shown in FIG. 9.As best shown in FIG. 9, a plurality of vertical 116 and horizontal 118panel ribs also extend integrally inward from an inner surface of thevehicle panel 12″ adjacent the frangible marginal edge 18″ of the doorperimeter and are spaced apart around the door perimeter. The door ribs112, 114 and panel ribs 116, 118 stiffen the door 16″ and vehicle panel12″ against air bag opening shock and help concentrate opening forcesalong the frangible marginal edge 18″ between the panel 12″ and the door16X. The door ribs 112, 114 and panel ribs 116, 118 are integrallyformed with the door 16″ and the vehicle panel 12″ as a single unitarypiece by injection molding.

In practice, when the air bag inflates it forces the reaction plate 28″to bend outward and upward around the first 36″ and second 102″horizontal hinge lines. As the reaction plate 28″ pivots outward itconcentrates the inflation force along a lower edge portion 120 of thefrangible door edge 18″. This helps to predictably separate the door 16″from the vehicle dash panel 12″ by tearing first along a lower edgeportion 120 of the marginal edge 18″ of the door 16″ then allowing thetear to propagate up two side edge portions 122 of the door edge 18″.The tear then propagates from the side edge portions 122 inwardly alongan upper edge portion 124 of the marginal door edge 18″ until the door16″ completely separates from the vehicle dash panel 12″. Because thetwo tethers 50″ connect the door 16″ directly to the reaction plate 28″,they prevent the door 16″ from flying free. Similar to the secondembodiment, the stop members 96″ of the third embodiment limit how farthe reaction plate 28″ can bend, leaving the reaction plate 28″ in agenerally vertical position. Unlike the second embodiment, however, theupwardly-bent reaction plate 28″ and the tethers 50″ of the thirdembodiment hold the air bag deployment door 16″ away from vehicleoccupants. Alternatively, tearing may occur along the lower edge portion120, side edge portions 122 and upper edge portion 124 virtuallysimultaneously.

In other embodiments, in place of the pin and slot arrangement describedfor the stop member above, any one of a number of differentconfigurations may be employed to arrest reaction plate 28 travel in aposition to prevent an air bag door 16 from returning to its originalposition.

A fourth embodiment of an inflatable restraint assembly is generallyshown at 10 s in FIGS. 12–16. Reference numerals with the suffix “5” inFIGS. 12–16 indicate alternative configurations of elements that alsoappear in the third embodiment. Where portions of the third embodimentdescription use reference numerals to refer to the figures, we intendthose portions to apply equally to elements designated by the suffix “s”in FIGS. 12–16.

The inflatable restraint assembly generally indicated at 10 s includesfirst and second vertically-disposed elongated flexible nylon tethers,generally indicated at 50 s, 51 s in FIG. 16, and representativelyindicated at 50 s in FIGS. 12 and 13. The tethers 50 s, 51 s slidablyengage the door 16 s rather than being fixed to the door 16 s asdisclosed in the description of the third embodiment. The apparatus 10 sincludes a flat, elongated flexible nylon fabric strap, generallyindicated at 126 in FIGS. 12–16. The strap 126 has a length extendingbetween two strap ends and is horizontally disposed flat against thedoor 16 s. As is best shown in FIG. 16, the strap 126 is fastened to thedoor 16 s at first, second, third and fourth spaced attachment points128, 130, 132, 134.

Each flexible tether 50 s, 5 is includes a tether loop, representativelyshown at 157 in FIGS. 12 and 13 and at 157 and 159, respectively, inFIG. 16. The loop portion 157 of each tether 50 s, 51 s extends from atleast one common tether loop attachment portion. In the presentembodiment, the tether loop attachment portions each comprise first andsecond tether loop ends, representatively shown at 156, 158 in FIGS. 12and 13. Fasteners 161 extend through a strap retention member 163, bothtether loop ends 156, 158, the reaction plate 28 s and the air bagdispenser 20 s. The fasteners 161 fasten the tether loop ends 156, 158together, and fasten the loop ends 156 and reaction plate 28 s to theair bag dispenser 20 s adjacent the reaction plate inner edge 34 s. Inother embodiments the first tether loop end 156 of each tether 50 s, 51s may be attached at a different location than the second tether loopend 158 of each tether 50 s, 51 s.

A middle portion 136 of the first flexible tether 50 s slidably extendsbetween the door 16 s and the strap 126, perpendicular to the length ofthe strap 126, and passes between the first and second attachment points128, 130. Likewise, a middle portion 138 of the second flexible tether51 s slidably extends between the door 16 s and the strap 126,perpendicular to the length of the strap 126, and passes between thethird and fourth attachment points 132, 134. In other words, the strap126 holds the flexible tethers 50 s, 51 s against the door 16 s whileallowing the flexible tethers 50 s, 51 s to slide longitudinally througha pair of slots 140, 142. The slots 140, 142 are formed between thestrap 126, the door 16 s and the attachment points 128–134 as best shownin FIGS. 12, 13 and 16.

The apparatus (10 s) includes first, second, third and fourth screwbosses, shown at 144, 146, 148 and 150 in FIG. 16 and representativelyshown at 144 in FIGS. 14 and 15. The bosses 144–150 extend integrallyinward from a door inner surface 38 s to the respective first, second,third and fourth attachment points 128–134. The screw bosses 144–150 areintegrally formed with the door 16 s as a unitary piece and are alignedhorizontally along the door inner surface 38 s. As shown in FIGS. 14–16,screw-type fasteners 152 extend through respective annular washers 154and attach the strap 126 to the respective first, second, third andfourth bosses 144–150 by threadedly engaging the bosses 144–150.

As with the first and second embodiment, a generally rectangularreaction plate 28 s is attached to an air bag dispenser assembly 20 salong a reaction plate inner edge 34 s, as shown in FIGS. 12–15. Anouter portion 35 s of the reaction plate 28 s is outwardly pivotableaway from the air bag dispenser assembly 20 s by bending the reactionplate 28 s along a hinge line 36 s extending parallel to the reactionplate inner edge 34 s. Prior to air bag inflation, the reaction plate 28s is bent at the hinge line 36 s approximately 850 downward fromhorizontal. Following air bag inflation, the reaction plate 28 s is bentapproximately 850 upward from horizontal.

Each flexible tether 50 s, 51 s has a length extending between first andsecond tether ends, representatively shown at 156 and 158, respectively,in FIGS. 12 and 13. The first and second tether ends 156, 158 of eachflexible tether 50 s, 51 s are fastened to the air bag dispenserassembly 20 s adjacent the reaction plate inner edge 34 s forming tetherloops as shown in FIGS. 12 and 13. A portion 160 of the first flexibletether 50 s slidably engages the outer portion 35 s of the reactionplate 28 s. Likewise, a corresponding portion of the second flexibletether 51 s slidably engages the outer portion 35 s of the reactionplate 28 s at a point spaced laterally from the point where the firstflexible tether 50 s engages the outer portion 35 s of the reactionplate 28 s.

As shown in FIGS. 12 and 13, the first flexible tether 50 s slidablyextends through a first opening or slot 168 in the outer portion 35 s ofthe reaction plate 28 s adjacent a reaction plate outer marginal edge 32s. Likewise, the second flexible tether 51 s slidably extends through asecond slot, spaced laterally from the first slot along the reactionplate outer marginal edge 32 s.

According to the fourth embodiment, when the air bag inflates, it forcesthe outer portion 35 s of the reaction plate 28 s to bend outward andupward around the horizontal hinge line 36 s. The outer portion 35 s ofthe reaction plate 28 s will then continue pivoting, due to angularmomentum acquired from air bag deployment, into a position angularlyspaced from the air bag deployment path and more than 45 degrees fromits position before air bag deployment. The angularly spaced position ofthe outer portion 35 s of reaction plate is best shown in FIGS. 13 and15. As the reaction plate 28 s pivots outward, it concentrates theinflation force along a lower edge portion 120 s of the frangible dooredge 18 s. This begins tearing that advances around the entire door edge18 s and separates the door 16 s from the vehicle dash panel 12 s.Similar to the third embodiment, the first and second tethers 50 s, 51 sof the fourth embodiment connect the door 16 s to the reaction plate 28s to decelerate and prevent the door 16 s from flying free.

Unlike the third embodiment, however, the tethers 50 s, 51 s of thefourth embodiment allow the door 16 s to slide along a portion of theirlengths. The sliding prevents the loads exerted by door 16 s on thetethers 50 s, 51 s from concentrating at any one attachment point alongthe tethers 50 s, 51 s. The sliding also spreads the door arrestingshock over time, reducing the probability of the door 16 s fracturing orpulling loose from the tethers 50 s, 51 s.

Although air bag inflation eventually causes the door to tear free alongan upper edge portion 44 s of the door perimeter 18 s, the upper edgeportion 44 s initially acts as a living hinge. The door 16 s initiallyswings outward and upward about the upper edge portion 44 s whileremaining in direct contact with the reaction plate 28 s.

During this initial opening swing, the plate 28 s and the door 16 spivot around different axes because the upper edge portion 44 s isoffset from the reaction plate hinge line 36 s. Because the upper edge44 s and hinge line 36 s are offset, and because the tethers 50 s, 5 isare slidably engaged with the plate 28 s and the door 16 s, the tethers50 s, 51 s are able to hold the plate 28 s and door 16 s in closeproximity to one another without arresting or overly restricting theirmovement.

The tethers 50 s, 51 s offer little resistance from the time the door 16s is initially forced open until the door 16 s and reaction plate 28 sreach an approximately horizontal position. However, when the reactionplate 28 s reaches this horizontal position, the door 16 s tears loosefrom the upper edge 44 s and is arrested by the tethers 50 s, 51 s. Asthe reaction plate 28 s moves through the horizontal and continues toswing upward toward its fully open near-vertical position, the reactionplate 28 s rapidly decelerates. As the reaction plate 28 s decelerates,the tethers 50 s, 51 s allow the door 16 s to swing upwards, absorbingenergy as the tethers 50 s, 51 s slide through the slots 168, 170 in thereaction plate and through the gap between the horizontal strap 126 andthe door 16 s.

Preferably, the tethers 50 s, 51 s and horizontal strap 126 are bothmade of nylon fabric. However, any one of a number of other suitablematerials may be used to construct the tethers 50 s, 51 s and/or thestrap 126, to include thin metal straps. In addition, a slotted insertmay be used, in place of a strap, to slidably retain the tethers 50 s,51 s. In other words, the tethers 50 s, 51 s; strap 126; reaction plate28 s; door 16 s; and offset pivot points 36 s, 44 s make up acompound-swing tether system that eliminates lash and is absorbs dooropening forces.

Other possible variations on the fourth embodiment include the strap 126being made of some flexible material other than fabric. Moreover, thestrap 126 need not be flat, but may be of any cross-sectional shape,e.g., a cord-like structure having a circular cross-section. Thereaction plate 28 s and/or tether ends 156, 158 could be attached to thevehicle panel 12 s rather than the air bag dispenser 20 s along thereaction plate inner edge 34 s. In addition, in other embodiments thetethers 50 s, 51 s need not slidably engage the reaction plate 28 s.Instead, the tethers 50 s, 5 is may be fixed to the reaction plate 28 sat some point along their respective lengths.

An inflatable restraint assembly for passengers in automotive vehicleshaving a reaction plate constructed of injection-molded plasticaccording to the present invention is generally indicated at 410 in FIG.31. The reaction plate is generally indicated at 411 in FIGS. 31 and 32.An inflatable restraint assembly having an alternative reaction plateattachment means constructed according to the invention is generallyindicated at 410′ in FIG. 33. The reaction plate is generally indicatedat 411′ in FIGS. 33 and 34. Reference numerals annotated with a primesymbol (′) in FIGS. 33 and 34 indicate alternative configurations ofelements that also appear in the embodiment of FIGS. 31 and 32. Where aportion of the description uses a reference numeral to refer to thefigures, we intend that portion of the description to apply equally toelements designated by primed numerals in FIGS. 33 and 34.

The assembly 410 includes a support structure generally indicated at 412in FIGS. 31 and 32. The support structure 412 includes an interiorvehicle panel or retainer panel shown at 414 in FIG, 31, and an air bagdeployment door shown at 416 in FIG. 31. The air bag deployment door 416is integrally formed in the retainer panel 414 and includes a perimeter418, at least a portion of which is defined by a frangible marginal edgeor tear seam 420. The support structure 412 also includes an air bagdispenser shown at 422 in FIG. 31. The air bag dispenser 422 issupported adjacent a door inner surface 424 opposite a door outersurface 426. An air bag (not shown) is supported in an air bagreceptacle or canister 428 of the air bag dispenser 422. The air bag hasan inner end operatively connected to the air bag dispenser 422 and anouter end disposed adjacent the air bag deployment door 416. The air bagdispenser 422 is configured to direct air bag deployment along adeployment path through the retainer panel 414.

The reaction plate 411 is disposed between the air bag and the air bagdeployment door 416 and is configured to receive the force of air bagdeployment from the air bag dispenser 422 and to direct and distributethat force against the door inner surface 424 to at least partiallyseparate the door 416 from the vehicle panel 414 along the frangiblemarginal edge 420 of the door 416. The reaction plate 411 has anintegral tether 430 connected between the support structure 412 and anoutwardly pivotable panel portion 435 of the reaction plate 411. Thetether 430 is configured to bend under the force of air bag inflationallowing the pivotable panel portion 435 to pivot into a positionangularly spaced from the air bag deployment path. The pivotable panelportion 435 of the reaction plate 411 is configured to close a canisteropening 434 of the air bag canister 422. The reaction plate 411comprises a plastics material.

The reaction plate 411 may be molded from a thermoplastic elastomer(TPE) to enable the reaction plate 411 to meet cold performancerequirements. The use of TPE allows the reaction plate 411 to meet thesestandards because TPE's are generally more ductile at low temperaturesor have lower glass transition temperatures (T_(g)) than the plasticsused for the retainer panel 414. However, in other embodiments thereaction plate 411 may be made of any one of a number of other suitablethermoplastic or thermoset plastics known in the art.

The integral tether or hinge 430 is connected to the support structure412 by a sliding hinge 436. The sliding hinge 436 is configured to allowthe reaction plate 411 to slide outwardly (rearwardly in the case of adash-mounted assembly) when a deploying air bag forces the reactionplate 411 to pivot outward. Because it allows the reaction plate 411 tomove outward as it pivots upward the sliding hinge 436 moves thereaction plate 411 into a position where it will not bind mechanicallyagainst a portion of the vehicle panel 438 that is disposed directlyabove and in the path of the opening reaction plate 411.

The integral tether 430 is connected to the support structure 412 by twofasteners 440. The sliding hinge 436 includes two slotted fastener holes442 in the integral hinge 430 to receive the fasteners. The slottedfastener holes 442 are configured to slidably receive the shaft portionsof each fastener 440. When a deploying air bag impacts a back surface446 of the reaction plate 411 and begins pushing the reaction plate 411and door 416 outward the slotted fastener holes 442 allow the integraltether 430 to slide outwardly relative to the fasteners 440.

The pivotable panel portion 435 of the reaction plate 411 includesintegral ribs shown at 448 in FIGS. 31 and 32. The integral ribs 448 areconfigured to stiffen the reaction plate 411 against deformation causedby uneven impact forces from a deploying air bag. The integral ribs 448extend integrally inward from an inner surface 446 of the pivotablepanel portion 435 of the reaction plate 411. As is best shown in FIG, 32the integral ribs 448 include vertical and horizontal intersecting ribsin a rectangular matrix or egg crate pattern.

According to the embodiment of FIGS. 33 and 34, the integral tether 430′includes fanfolds 452 configured to allow the tether 430″ to elongatewhen a deploying air bag forces the reaction plate 411′ outward (again,rearward in the case of a dash-mounted assembly). The fanfolds 452 maybe integrated into the molding of the reaction plate 411′ thuseliminating the mechanical bind described above with regard to theembodiment of FIGS. 31 and 32, without having to form and assemble asliding mechanism such as that shown in the embodiment of FIGS. 31 and32. In other embodiments, the tether 430 may include an accordion orbellows-type configuration rather than the fanfolds 452 described above.

A panel and integral air bag door assembly having an alternative hingeand tear seam configuration is generally shown at 210 in FIGS. 18, 19and 22. A panel and integral air bag door assembly having anotheralternative tear seam configuration is shown at 210′ in FIGS. 20 and 23and a panel and integral air bag door assembly having yet anotheralternative tear seam configuration is shown at 210″ in FIGS. 21 and 24.Reference numerals annotated with a prime symbol (′) in FIGS. 20 and 23and with a double-prime symbol (″) in FIGS. 21 and 24 indicatealternative configurations of elements that also appear in theembodiment of FIGS. 18, 19 and 22. Where a portion of the descriptionuses a reference numeral to refer to the figures, we intend that portionof the description to apply equally to elements designated by primednumerals in FIGS. 20 and 23 and double-primed numerals in FIGS. 21 and24.

FIGS. 18, 19 and 22 show the closed position of an air bag door 212integrally formed in an automotive instrument panel 214 according to thefirst embodiment. The composite air bag door 212 and instrument panel214 comprises a first plastic material 216 and includes a frangiblemarginal edge 218 that defines the air bag door 212. The frangiblemarginal edge 218 is constructed to insure that the air bag door 212breaks and/or tears open in a generally predictable way. The air bagdoor 212 is movable from the closed position to provide a path for anair bag to deploy through. The air bag door 212 is movable out of theclosed position by causing the air bag door 212 to at least partiallyseparate from the instrument panel 214 along a door perimeter 220 thatis at least partially defined by the frangible marginal edge 218. Theremainder of the door perimeter 220 is defined by an integral retainingstructure in the form of a hinge 222. The hinge 222 is configured topreclude at least a portion of the air bag door 212 from departing theimmediate vicinity of the instrument panel 214 during air bagdeployment. The immediate vicinity of the instrument panel 214 is anarea surrounding the instrument panel 214 that is spaced far enough fromany passenger compartment occupant that no portion of the air bag door212 can contact an occupant during air bag deployment. The hinge 222allows the air bag door 212 to open when the air bag inflates butinsures that the door 212 does not separate under the force of air bagdeployment. The hinge 222 includes a hinge panel that is generallyindicated at 224 in FIGS. 18 and 22. As is best shown in FIG. 18, thehinge panel 224 comprises a second material that is embedded at leastpartially within the first material 216 and spans the door perimeter220. The second material may include any one or more of a number ofsuitable materials to include a thermoplastic rubber such asSantoprene®, glass matte, cloth or fabric and metal.

The hinge panel 224 is invisible as viewed from an outer class-A surface226 of the instrument 214. As is best shown in FIG. 18, a first end 228of the hinge panel 224 is embedded in a portion of the first material216 that forms the door 212. A second end 230 of the hinge panel 224 isembedded in a portion of the first material 216 that forms theinstrument panel 214. A mid portion 232 of the hinge panel 224 isdisposed between the first and second ends 228, 230. As is best shown inFIG. 18, the mid portion 232 of the hinge panel 224 has a hinge panelouter surface 234 covered with a portion 236 of the first material 216that forms the outer class-A surface of the door 212 and instrumentpanel 214. The portion 236 of the first material that covers the outersurface 234 of the mid portion 232 of the hinge panel 224 continues theouter class-A surface 226 over the hinge panel 224 and between the door212 and instrument panel 214, concealing the presence of the hinge panel214 and the dividing line or seam 220 between the door 212 andinstrument panel 214. The mid portion 232 also has an exposed hingepanel inner surface shown at 238 in FIGS. 18 and 22. The exposed hingepanel inner surface 238 is disposed opposite the hinge panel outersurface 234. The hinge panel inner surface 238 is left exposed topromote bending along the hinge 222.

As shown in FIGS. 19 and 22, the frangible marginal edge 218 comprises aregion of reduced thickness outlining the integral air bag door 212 inthe instrument panel retainer 214. The frangible marginal edge 218guides tearing and/or breakage during air bag deployment. In addition, atubular channel (sometimes referred to as a gas structural channel) isgenerally indicated at 240 in FIGS. 19 and 22. The tubular channel 240is disposed on the air bag door 212 along the frangible marginal edge218. The tubular channel 240 comprises a tube, shown at 242 in FIG. 19,having a generally circular cross-section. The tube 242 is partiallydefined by an elongated hemispherical wall 244 that integrally extendsfrom an inner surface 246 of the air bag door 212. The hemisphericalwall 244 and the air bag door 212 and the instrument panel 214 areformed together as a single unitary piece by gas-assisted injectionmolding as is described in greater detail below. The tubular channel 240provides reinforcement and structure that creates a substantial strengthdifferential with the door perimeter 220.

In other embodiments, the tubular channel 240 may have a tubular crosssection that is other than circular and may extend integrally from theinstrument panel 214 rather than the air bag door 212. In either case,the tubular channel 240 is disposed opposite the outer class-A surface226 of the air bag door 212 and instrument panel 214. In this positionthe tubular channel 240 is hidden from vehicle occupants' view and helpsto conceal the presence of the supplemental inflatable restraint system.As shown in FIG. 22, the channel 240 extends 2700 around rear and sideedges of the air bag door 212. While a single “C-formed” door is shownin FIG. 22, the same approach can be used for “H-shaped” double doors,“X-shaped” doors, etc.

The panel and integral airbag door assembly 210′ of FIGS. 20 and 23include two tubular channels generally indicated at 240′ and 248,respectively. The tubular channels 240′, 248 are disposed adjacent andparallel to each other. The channels 240′, 248 run astride and define anelongated gap 218′ that defines an integral air bag door 212′ in aninstrument panel retainer 214′. The gap 218′ also serves as a frangiblemarginal edge between the two structural channels 240′, 248.

The panel and integral airbag door configuration of FIGS. 21 and 24 alsoinclude two tubular channels generally indicated at 240″ and 248″,respectively. The tubular channels 240″, 248″ are disposed adjacent andparallel to each other. The channels 240″, 248″ run astride and definean elongated gap 218″ that defines an integral air bag door 212″ in aninstrument panel retainer 214″. The gap 218″ also serves as a frangiblemarginal edge between the two structural channels 240″, 248″. Unlike thepanel and integral airbag door assembly 210′ shown in FIGS. 20 and 23,the panel and integral airbag door assembly 210″ shown in FIGS. 21 and24 include an elongated groove, shown at 250 in FIGS. 21 and 24,disposed in an outer class-A surface 226″ opposite the elongated gap218″. The elongated groove 250 further reduces the thickness of theplastic material where concealment of the presence of an air bag doorfor an inflatable restraint system is not a concern.

In practice, the hinge 222 of the inflatable restraint assembly may beconstructed by first providing a mold configured to form the shape ofthe integral air bag door 212 and instrument panel 214. The hinge panel224 comprising a sheet of the second material is then placed in the moldin a position spanning a region of the mold configured to form the doorperimeter 220. The first material 216 is then introduced in molten forminto the mold such that the hinge panel 224 is at least partiallyembedded in the first material 216. The first material 216 is thenallowed to cure within the mold. Finally, the cured first material 216and at least partially embedded hinge panel 224 are removed from themold.

The tear seam 218 of the inflatable restraint assembly may beconstructed according to the present invention by first providing a moldconfigured to form the shape of the integral air bag door 212 andinstrument panel 214 and the tubular channel 240 or channels 240′, 248;240″, 248″. Resin is then injected into the mold. Gas is then injectedinto a portion of the resin disposed in a portion of the mold configuredto form the tubular channel 240 or channels 240′, 248; 240″, 248″. Asthe gas is injected it forms the tubular channel tube(s) 242 and helpspropel resin into narrow mold regions along the tear seam 218. The resinis then allowed to cure within the mold before it is removed. The use oftubular channels to form tear seams has the advantage of providingrelatively large tear-guide structures without using large amounts ofmaterial to create thick regions that would result in sink formation. Iflarge amounts of material were used to thicken the panel on either sideof the desired tear seam, shrinkage during curing would result insurface discontinuities in the form of depressions or “sinks”.

Another inflatable restraint assembly embodiment, generally shown at 310in FIGS. 25 and 26, includes a 360° tear seam 316 bounded by tubularchannels 350. FIGS. 25, 26 and 28 show the assembly 310 installed in anautomotive instrument panel and FIG. 27 shows an alternative embodiment310′ shown installed in an automotive door panel. FIG. 29 shows analternative screw boss embodiment. Yet another inflatable restraintassembly embodiment, generally shown at 310″ in FIG. 30, includes a 270°tear seam 316″ bounded by tubular channels 350″, 360″. Referencenumerals annotated with a prime symbol (′) in FIG. 27 and with adouble-prime symbol (″) in FIG. 30 indicate alternative configurationsof elements that also appear in the embodiment of FIGS. 25, 26 and 28.Where a portion of the description uses a reference numeral to refer tothe figures, we intend that portion of the description to apply equallyto elements designated by primed numerals in FIG. 27 and double-primednumerals in FIG. 30.

The assembly 310 comprises an air bag door generally indicated at 312 inFIG. 26. The air bag door 312 is integrally formed in a plastic trimpanel retainer generally indicated at 314 in FIG. 26. The air bag door312 and trim panel retainer 314 are formed together as a single unitarypiece by injection molding. The weakened area or tear seam in theretainer, shown at 316 in FIGS. 25 and 26, defines at least a portion ofthe outline of the air bag door 312. The tear seam 316 is configured tohelp guide tearing and/or breakage under the force of air bag inflation.The tear seam 316 is formed in an inner surface of the retainer 314 toprovide an air bag door 312 that is hidden from the view of vehicleoccupants. In other embodiments, the tear seam 316 or a styling line maybe included on an outer surface of the retainer portion 314.

An air bag canister, generally indicated at 318 in FIGS. 25 and 26, issupported behind the air bag door 312 and has a canister opening 320directed toward and facing the air bag door 312. In a preferredembodiment, the canister 318 is an aluminum extrusion. A cover 319 witha center break 321 covers the canister opening 320. The cover 319protects an air bag 322 stored in the canister 318. The configurationenables the air bag 322 to deploy through the door 312 from within thecanister 318 when inflated in a known manner. The air bag door 312 isshaped to approximate the shape of the air bag canister opening 320 topreclude interference between the deploying air bag 322 and inner edgesof the openings created in the retainer 314 when the air bag door 312 isforced open. The air bag 322 will at least initially retain the generalshape of the canister opening 320 that the air bag 322 is deployingfrom. Therefore, the air bag 322 is less likely to get caught on theinner edges of the air bag door opening because the opening has the sameshape as the canister opening 320.

The tear seam 316 partially defines an arcuate, cornerless shape for theair bag door 312 as shown in FIGS. 25 and 35. The tear seam 316 isformed by integral molding but may alternatively be formed bygas-assisted injection molding, machining using computer numericalcontrol equipment (CNC), laser scoring and the like. The arcuate shapeof the door 312 makes tear propagation more predictable by eliminatingsharp corners that can be truncated during air bag deployment. In otherwords, as a crack forms along the tear seam during air bag deployment,rather than negotiate a corner, the crack tends to leave the tear seamand propagate across or “cut off” the corner. The severed corner mayeither remain attached to the surrounding material or may break free.More specifically, in the case of a rectangular shaped door, corners are“cut-off” and may fail to tear out when a tear seam fracture propagateshorizontally outward from the center of a horizontal tear seam at theforward edge of the door, toward the lower corners of the door thenleaves that tear seam and “cuts the corner” to an adjacent vertical tearseam instead of continuing to propagate along the horizontal tear seamand all the way around the corner to the vertical tear seam. Throughexperimentation it has been determined that a tear seam corner having aradius of 13 mm or less will typically fail, i.e., be “cut-off”, indeployments at or below −40° F. It has also been found that cornerhaving radii of 20 mm or greater will not fail—even at −40° F.

As best shown in FIG. 35, the tear seam 316 describes a symmetricarcuate path having a vertical line of symmetry shown at 376. The tearseam 316 is essentially cornerless. At no point along the tear seam 316is there a curve having a radius less than 70 mm. In other words, noincremental length of the tear seam 316 has a curve defined by a radiusof less than 70 mm. In other embodiments, any portion of any of thecurves defining the tear seam 316 may be defined by radii ofconsiderably less than 70 mm so long as they are not less than the 13 mmvalue at which tear seam curves have been found to fail at temperaturesbelow −40° F. Optimally, to insure a margin of safety, no portion of anycurve should be defined by a radius of less than 20 mm. Another way toexpress this is to say that, at no point along any curve defining thetear seam 316 should the rate of change of the slope of that curve bepermitted to exceed that of a 20 mm diameter circle.

Upper left 378 and upper right 380 portions of the tear seam 316,extending between approximate 9 and 11 o'clock positions and betweenapproximate 1 and 3 o'clock positions of the air bag door 312,respectively, are defined by respective curves that transition in radiusfrom 70 mm at approximate 11 o'clock and 1 o'clock positions,respectively, to 78 mm at approximate 9 o'clock and 3 o'clock positions,respectively. The 70 mm radii, the 78 mm radii and all the transitionalradii disposed between those radii are measured from a first centerpoint A for the upper left portion 378 and a second center point B forthe upper right portion 380 of the tear seam 316.

An upper mid portion 382 of the tear seam 316, extending between theapproximate 11 and 1 o'clock positions, is defined by a generallystraight line connecting the upper left 378 and upper right 380 portionsof the tear seam 316.

Lower left 384 and lower right 386 portions of the tear seam 316,extending between the 8 and 9 o'clock positions and the 3 and 4 o'clockpositions, respectively, are defined by respective curves thattransition from a radius of 78 mm to a radius of 250 mm. The 78 mmradius is measured from center point A to the approximate 9 o'clockposition for the lower left portion 384 and from center point B to theapproximate 3 o'clock position of the door 312 seam for the lower rightportion 386 of the tear seam 316. The 250 mm radius of the lower leftportion 384 is measured from a third center point shown at C in FIG. 35to an approximate 8 o'clock position of the tear seam 316. Point C islocated 88 mm above the upper mid portion 382 of the tear seam 316 alongthe line of symmetry 376. The 250 mm radius of the lower right portion386 is measured from the third center point C to an approximate 4o'clock position of the tear seam 316. Between the 8 and 9 o'clockpositions and the 3 and 4 o'clock positions, the lower left and lowerright portions 384, 386 follow blend transition curves that are definedby radii that do not have a common center point. More specifically, the8 and 9 o'clock positions and the 3 and 4 o'clock positions areconnected by French curves.

A lower mid portion 388 of the tear seam 316, extending between theapproximate 4 and 8 o'clock positions, is defined by curve of constant250 mm radius from center point C.

As shown in FIG. 26, a steel reaction plate 324 is supported behind andis fastened to the air bag door 312, opposite an outer class-A surface326 of the door 312. The reaction plate 324 is a flat sheet of metalhaving an arcuate shape generally matching that of the air bag door 312.At least a portion of an outer peripheral edge 328 of the reaction plate324 is aligned adjacent the tear seam 316 to help distribute air bagdeployment forces along the tear seam 316.

Alternatively, the reaction plate may include a perimeter edge treatmentconfigured to further concentrate deployment forces along the tear seam.

The reaction plate 324 includes an integral metallic extension 330 ortether strap connected to the trim panel retainer 314 at a pointadjacent the air bag door 312. The integral extension 330 serves as botha living hinge and a tether to the air bag door 312 during air bagdeployment.

A pair of elongated tubular channels, shown at 350 in FIG. 26, areformed by gas assisted injection molding along either side of the tearseam 316 to further insure that tearing occurs only along the tear seam316. The tubular channels 350 increase structural rigidity adjacent thetear seam 316 without requiring a large mass of material. Because thetubular channels 350 are hollow and do not require a relatively largeconcentration of material, their formation by injection molding does notresult in distortions of the outer class-A surface 326 as wouldotherwise be the case.

As shown in FIG. 26, one of the tubular channels 350 is integrallyformed along a peripheral outer edge of the door 312 and the other ofthe tubular channels 350 is integrally formed with a canister supportbracket 352. The canister support bracket 352 is semi-circular in frontview (not shown) to conform generally to exterior dimensions of aforward lower edge 354 of the canister 318.

The door 312 includes ribs 332 and bosses 334 integrally extending froma back surface 336 of the door 312 opposite the outer class-A surface326. However, alternatively, the reaction plate 324 may include ribsextending integrally from an outer surface 313 of the reaction plate324. (The FIG. 26 drawing is consistent with the ribs 332 extendingeither outward from the reaction plate 324 outer surface 313 or inwardfrom the door 312 inner surface 336.) The reaction plate 324 is spacedfrom the back surface 336 by the ribs 332, bosses 334, and is fastenedto the door 312 by fasteners 338 extending through the reaction plate324 and into the bosses 334. Referring to FIG. 29 other embodiments mayinclude tubular channels 360 integrally extending from the back surface336 of the door 312 and/or the retainer 314 and supporting the bosses334 which integrally extend inward from the tubular channels 360. Atether strap 330 and reaction plate 324 are attached to the bosses 334by fasteners 338. One of the tubular channels 360 integrally extends3600 around the peripheral edge of the door 312 to help guide tearingcompletely around the entire door 312 and thus allowing the door 312 tocompletely separate from the trim panel retainer 314. However, in otherembodiments, the tubular channel 360 that is formed integrally with thedoor 312 may be formed only 270° with respect to the canister 318, i.e.,at the sides and bottom of the canister opening. This is to concentratethe tearing forces at the side 316 a, 316 b and bottom 316 c of the tearseam 316 and allow the door 312 to pivot around a living hinge formed ata junction of the retainer 314 and door 312 upon air bag inflation.

Referring to FIG. 25, the air bag canister opening 320 has the samearcuate, generally circular or oval shape as the air bag door 312 tohelp the stowed air bag 322 to fit through the opening left by the airbag door 312. However, because the air bag 322 expands as it deploys,the air bag door 312 is larger in area than the air bag canister opening320.

A foam layer, as shown at 340 in FIG. 26, may be disposed on and adheredto an outer surface 341 of the retainer 314 and door 312. A skin orlayer of cover material 342 is disposed over and adhered to an outersurface of the foam layer 340. In other embodiments, the outer surface341 of the retainer 314 and door 312 may also be an outer class-Asurface of the retainer 314 and door 312, i.e., in hard first surface IPapplications having no foam or skin. In some cases, the skin will beweakened along the same outline as tear seam 316.

In the embodiment of FIGS. 25 and 26 the trim panel that includes theretainer 314 and door 312, is an instrument panel. However, in otherembodiments, the inflatable restraint assembly may be configured to bemounted in a door panel as shown at 310′ in FIG. 27, rather than aninstrument panel as shown at 310 in FIG. 25. In the door panel, theassembly 310′ acts as a side-impact-absorbing system.

According to the embodiment of FIG. 30, the canister opening 320″includes no cover 319. Instead, a reaction plate 324″ is configured todose the canister opening 320″. The reaction plate 324″ includes anintegral extension or tether 330″ having fanfolds 331 configured toallow the tether 330″ to elongate when a deploying air bag forces thereaction plate 324″ outward.

As with the embodiment of FIGS. 25, 26 and 28, the embodiment of FIG. 30includes a pair of elongated tubular channels, shown at 350″, 360″ inFIG. 30. The tubular channels 350″, 360″ are formed by gas-assistedinjection molding along either side of a tear seam 316″ that defines anintegrally formed door 312″ in a retainer panel 314″. As with theprevious embodiments, the tubular channels 350″, 360″ are included tofurther insure that tearing is confined to the tear seam 316″ when adeploying air bag forces the door 312″ to open. As shown in FIG. 30, oneof the pair of tubular channels 350″ is integrally formed along aperipheral outer edge of the door 312″ and the other of the pair oftubular channels 360″ is integrally formed with the retainer 314″ inwhich the door 312″ is integrally formed. The tear seam 316″ and thepair of tubular channels 350″, 360″ are formed around approximately 270°of the door 312″, leaving a bottom edge 362 of the door 312 without anytubular channel or tear seam. The bottom edge 362 of the door 312requires no tear seam as it is also a portion of a bottom edge of theretainer panel 314″ and is unattached to any adjacent structures.

A screw boss 334″ integrally extends inward from tubular channel 360″and provides one of two connecting points for the reaction plate tether330″ shown in FIG. 30. The second connecting point for the tether 330″is shown at screw boss 335 which integrally extends inward from theretainer 314″. Screw bosses 334″ and 335 also provide connecting pointsfor an upper support bracket shown at 364 in FIG. 30. The embodiment ofFIG. 30 also includes an additional tubular channel 364 that integrallyextends from the inner surface 336″ of the door 312″. A third screw boss337 integrally extends inward from tubular channel 364 and provides aconnecting point for the reaction plate 324″.

The description and drawings illustratively set forth our presentlypreferred invention embodiments. We intend the description and drawingsto describe these embodiments and not to limit the scope of theinvention. Obviously, it is possible to modify these embodiments whileremaining within the scope of the following claims. Therefore, withinthe scope of the claims, one may practice the invention otherwise thanas the description and drawings specifically show and describe.

1. An inflatable restraint assembly for an automotive vehicle, theapparatus comprising: a support structure; an air bag deployment doorintegrally formed in a vehicle panel, the air bag deployment door havinga perimeter, at least a portion of the perimeter defined by a frangiblemarginal edge; an air bag canister supported adjacent a door innersurface opposite a door outer surface, the canister including a canisteropening; an air bag supported in an air bag receptacle of the air bagcanister, the air bag having an inner end operatively connected to theair bag canister and an outer end disposed adjacent the air bagdeployment door, the air bag canister configured to direct air bagdeployment along a deployment path through the vehicle panel; a reactionplate disposed between the air bag and the air bag deployment door; thereaction plate including a pivotable panel portion separate from the airbag door, and configured to pivot outward under the force of air baginflation; the reaction plate connected to the support structure; and afirst tubular channel disposed along at least a portion of the air bagdoor perimeter.
 2. An inflatable restraint assembly as defined in claim1, in which the first tubular channel is disposed opposite an outersurface of the air bag door and vehicle panel.
 3. An inflatablerestraint assembly as defined in claim 1, further including a secondtubular channel disposed adjacent and parallel to the first tubularchannel, the door perimeter being disposed between the first and secondtubular channels, one of the tubular channels being integrally formedwith the door and the other tubular channel being integrally formed withthe vehicle panel.
 4. An inflatable restraint assembly as defined inclaim 3 in which the frangible marginal edge is defined by an elongatedgap defined by and disposed between the first and second tubularchannels.
 5. An inflatable restraint assembly as defined in claim 4further including an elongated groove disposed in the door outer surfaceopposite the elongated gap.
 6. An inflatable restraint assembly asdefined in claim 1 in which the frangible marginal edge defines theentire air bag deployment door perimeter.
 7. An inflatable restraintassembly as defined in claim 3 in which the frangible marginal edge andthe first and second tubular channels are formed around approximately270° of the air bag door.
 8. An inflatable restraint assembly as definedin claim 1 in which a screw boss integrally extends inward from thetubular channel and is configured to receive a fastener connecting thereaction plate to the screw boss.
 9. An inflatable restraint assembly asdefined in claim 1 in which the tubular channel extends integrallyinward from the inner surface of the door and a screw boss integrallyextends inward from that tubular channel, the screw boss beingconfigured to receive a fastener connecting the reaction plate to thescrew boss.
 10. An inflatable restraint assembly as defined in claim 1in which the frangible marginal edge of the door comprises a region ofreduced cross section.
 11. An inflatable restraint assembly as definedin claim 1 in which the air bag deployment door includes a marginal edgethat forms a hinge between the vehicle panel and the door.
 12. Aninflatable restraint assembly as defined in claim 11 in which: the doorand panel comprise a first material; and the hinge includes a hingepanel comprising a second material embedded at least partially withinthe first material and spanning the door perimeter.
 13. An inflatablerestraint assembly as defined in claim 12 in which the hinge panelincludes: a first end embedded in a portion of the first material thatforms the door; a second end embedded in a portion of the first materialthat forms the vehicle panel; and a mid portion disposed between thefirst and second ends, the mid portion having an outer surface thereofcovered with a portion of the first material that forms the outersurface of the air bag door and vehicle panel, the mid portion having anexposed inner surface disposed opposite the outer surface thereof. 14.An inflatable restraint assembly as defined in claim 12 in which thesecond material is selected from the group consisting of thermoplasticrubber, glass matte, fabric and metal.
 15. An inflatable restraintassembly as defined in claim 11 in which the hinge is invisible on anouter surface of the vehicle panel.
 16. An inflatable restraint assemblyas defined in claim 1 in which a flexible skin covers at least a portionof the vehicle panel in a layered disposition.
 17. An inflatablerestraint assembly as defined in claim 1 in which a foam layer covers atleast a portion of the vehicle panel.
 18. An inflatable restraintassembly as defined in claim 1 in which: the perimeter of the air bagdoor is generally shaped to approximate the shape of the air bagcanister opening; and the frangible marginal edge at least partiallydefines an arcuate shape for the air bag door.
 19. An inflatablerestraint assembly as defined in claim 18 in which the air bag canisteropening has the same general arcuate shape as the air bag door.
 20. Aninflatable restraint assembly for an automotive vehicle, the apparatuscomprising: a support structure; an air bag deployment door integrallyformed in a vehicle panel, the air bag deployment door having aperimeter, at least a portion of the perimeter defined by a frangiblemarginal edge; an air bag dispenser supported adjacent a door innersurface opposite a door outer surface; an air bag supported in an airbag receptacle of the air bag dispenser, the air bag having an inner endoperatively connected to the air bag dispenser and an outer end disposedadjacent the air bag deployment door, the air bag dispenser configuredto direct air bag deployment along a deployment path through the vehiclepanel; a reaction plate disposed between the air bag and the air bagdeployment door; the reaction plate including a pivotable panel portionconfigured to pivot outward under the force of air bag inflation; thereaction plate connected to the support structure; and at least one ribextending integrally inward from the door inner surface towards thereaction plate.